The Welding Performance of ductile iron and grey iron is not good. Extra high hardness and crack are the main problems.
Because of the low tensile strength, and high carbon content, the welding to grey iron may get some crack. So, the Welding Performance of grey iron is poor.
The welding to ductile iron will cause extra high hardness to the welding area, the hardness can reach 600-700 HBS, the welding area may get some crack too. From this point, the Welding Performance is not good either.
However, the ductile iron's mechanical properties, such as tensile strength and elongation, are much better than grey iron, so for the crack problem, the ductile iron will be better than grey iron. From this point, the welding to ductile iron is better than grey iron.
Two solutions will improve their welding problems:
1. Heat conditioned welding will make it better.
2. Using the electrode for cast iron, or called as cast iron electrode.